CHDH Seminar Series 2020: A Brief History of Time1 — Simon Cropper (Part 1)

1 with apologies to Steven Hawking

Presenter: Simon Cropper

Date: Monday 4 May

Time: 12 - 1 PM

Location: Via Zoom. Please use this link at the time of the event to join: https://unimelb.zoom.us/j/98021866058

Seminar Description:

When the day becomes the night and the sky becomes the sea, When the clock strikes heavy and there's no time for tea. And in our darkest hour, before my final rhyme, she will come back home to Wonderland and turn back the hands of time.  Through the Looking-Glass, and What Alice Found There, Lewis Carroll (1871)

The world we experience is (re)constructed from two dimensions of space (x and y) and their variation over time (t). Everything we perceive is generated from these three input-dimensions, which makes the percept of time itself far more fundamental to our whole experience than simply the passage of hours minutes and seconds in the external world. Furthermore, the neural representation of time is at least as dissociated from the physical quantity it is representing, if not more so, than the neural representation of space, despite the commonplace shorthand description of an internal ‘clock’.

From an experimental perspective the measurement of time perception presents several interesting challenges. The ability of humans to identify and reproduce short time intervals (in the region of a second) may be affected by many factors ranging from the gender of the individual observer, through the attentional state, to the fine spatiotemporal structure of the stimulus. The relative roles of these very different factors are a challenge to describe and define; several methodological approaches have been used to achieve this to varying degrees of success.

In week 1, Simon will review some of the approaches to measuring time and outline some of the challenges in this endeavour. In week 2, Simon will describe a new(-ish) paradigm affording not only a first-order measurement of the perceived duration of an interval, but also a second-order metacognitive judgement of perceived time. This approach, he will argue, expands the form of the data generally collected in duration-judgements and allows more detailed comparison of psychophysical behaviour to the underlying theory. This enhanced form of the data on a given judgement and the ability to track its progression on a trial-by-trail basis offers a way of looking at the different roles that subject-based, task-based and stimulus-based factors have on the perception of time.

Simon Cropper: Is ….. still here.